Fixed fluid-tight tank or the like and method of constructing same

ABSTRACT

1,155,116. Liquefied gas storage containers. TECHNIGAZ. 19 Sept., 1966 [22 Sept., 1965], No. 41704/66. Heading F4P. The fluid-tight inner vertical cylindrical shell 13, Fig. 1, of a heat insulated double-walled liquefied gas container and having a top 22 and generally flat bottom 21 is constructed of flexible sheet metal plates welded at their overlapping edges and having a first group of spaced parallel corrugations intersected at right angles by a second group of similar corrugations, and the inner shell is secured at spaced points to the external shell 2 by brackets 47, Fig. 7, extending through the heat insulation 14 between the two shells; the outer cylindrical shell which may be of steel or concrete having a flat bottom 3 resting on a prepared earth base 4. The first group of corrugations 16 of the lateral cylindrical wall 17 of the shell 13 extend continuously and vertically whilst the corrugations 18 of the second group extend round circumference of wall 17. The first group of corrugations of the base 21 comprise alternate radially extending corrugations 23, 23&lt;SP&gt;1&lt;/SP&gt; which divide the base into sectors 24 and those sectors on either side of a corrugation 23&lt;SP&gt;1&lt;/SP&gt; have further continuous corrugations 25 parallel thereto but of differing lengths and are intersected at right angles by parallel corrugations 26 which form the second group. The roof 22 of shell 13 is similarly constructed and all corrugations project inwardly. The bracket 47 shown in Fig. 7 comprises four radial ribs welded at one end to a steel plate 50 embedded in the concrete wall of shell 2 and secured at the other end of a screw 52 to the shell 13. A modified bracket shown in Fig. 11 comprising a tube 60 welded at its outer end to a steel plate 50 and closed at its inner end by a plate 62 carrying a stud 63 which projects through the shell 13 and secured by a nut 66. The heat insulation 14 comprises panels 58, 59 of rigid expanded polyurethane or expanded polyvinylchloride. A central orifice 28 in the roof of the container is closed by a plate 29 having filler pipes 32 and a manhole 31.

May 12, 1970 J. ALLEAUME 3,511,003

FIXED FLUIDTIGHT TANK OR THE LIKE AND METHOD OF CONSTRUCTING SAME Filed Sept. 15, 1966 s Sheets-Sheet 1 l/VI/ENTOE 7 41v A M EAUME May 12, 1970 J. ALLEAUME 3,511,003

FIXED FLUID-TIGHT TANK OR THE 'LIKE AND METHOD OF CONSTRUCTING SAME Filed Sept. 15, 1966 8 Sheets-Sheet z M/vE/vroe 'EAA/ Aug/m J. ALLEAUME May 12, 1970 FIXED FLUID-TIGHT TANK 0R"THE -"LIKE AND METEOD OF CONSTRUCTING SAME 8 Sheets-Sheet 5 Filed Sept. 15, 1966 IIIIIIIIIIIIIIIIIIIIIIII May 12, 1970 J. ALLEAUME 3,511,003 FIXED FLUID-TIGHT TANK OR "THE LIKE AND METHOD OF CONSTRUCTING SAME Filed Sept. 15. 1966 8 Sheets-Sheet 5 AWE/vine 54 A 4 z 64 a! May 12, 1970 J. ALLEAUME FIXED FLUID-TIGHT TANK OR" THE LIKE AND METHOD OF GONSTRUCTING SAME 8 Sheets-Sheet 6 Filed Sept. 15, 1966 //VVE/V7'0@ (TEA/V ALL FAN/WE J. ALLEAUME May 12, 1970 FIXED FLUID-TIGHT TANK OR THE LIKE AND METHOD OF CONSTRUCTING SAME 8 Sheets-Sheet '7 Filed Sept. 15, 1966 l/VVF/VT'O/e Sim/v Mae-4am;

Arm/e A/EYS May 12, 1970 J. ALLEAUME 3,511,003

: FIXED FLUID-TIGHT TANK ORTHE-LIKE AND METHOD OF 'CONSTRUCTING SAME Filed Sept. 15, 1966 8 Sheets-Sheet 8 INK/EN]? E 7514 4 EA (M5 Wyflm WA ATfdQ/VIFYS United States Patent 3,511,003 FIXED FLUID-TIGHT TANK OR THE LIKE AND METHOD OF CONSTRUCTING SAME Jean Alleaume, Saint-Cloud, France, assignor to Technigaz, Paris, France, a French body corporate Filed Sept. 15, 1966, Ser. No. 579,776 Claims priority, application France, Sept. 22, 1965, 32,309 Int. Cl. E04b 7/00 US. Cl. 52-198 23 Claims ABSTRACT OF THE DISCLOSURE A tank comprising: a cylindrical, vertical, self-supporting outer shell with a flat bottom resting on a basement; an impervious inner shell spaced from said outer tank and forming a flexible membrane provided with two perpendicularly intersecting sets of parallel corruga tions; and one layer of rigid heat insulation attached to said outer shell and filling the intermediate space left between said shells and supporting the pressure of said inner shell bearing thereagainst; said inner shell being connected to said outer shell at discrete points by means of spaced fastening brackets secured to said outer shell and extending through said insulation.

The present invention has essentially for its objects a fixed land device constituting a substantially closed, fluid-tight enclosure such as nuclear reactor envelope or caisson, or such as a tank, reservoir, vat or similar container, for storing and preserving fluids in general and more particularly liquefied gases at very low tem perature, for example at a pressure approximating the atmospheric value, and also a method of constructing a device of this character and the various applications resulting from their practical use.

Storing fluids and more particularly gases or hydrocarbons liquefied at low temperature, for example natural gases such as methane, substantially at the atmospheric pressure and at a temperature of l60 C. in rising tanks, that is, tanks constructed at least partially above ground level, is attended by delicate technological problems due both to heat distortion phenomena (expansion and contraction) resulting from the considerable temperature differences to which the tanks are subjected and also from the necessity of utilizing special materials capable of retaining satisfactory mechanical strength properties at very low temperatures.

Tanks are already known which are constructed at east in part above ground level for storing liquefied gases, notably liquid methane, of the type comprising at least one double wall and including an external shell having a self-supporting structure of ordinary steel or reinforced concrete, for example prestressed concrete, of

substantially cylindrical vertical configuration with a convex upper end wall, roof or top and resting through a flat lower end Wall or bottom on a base or basement; at least one internal metal shell constituting a fluid-tight barrier for containing said fluid and consisting of relatively thin corrugated metal sheets for exam ple of stainless steel acting as a flexible or yielding membrane having formed therein a network or pattern of generally orthogonally intersecting corrugations distributed into at least two groups or series of corrugations respectively substantially parallel to each other and preferably equally spaced in each series or group; and at least one intermediate layer of heat-insulating material filling the intermediate space provided between said shells and against which bears said internal shell. Therefore, the original feature of this building technique consists in dissociating the two problems respectively of heat or thermal expansion and mechanical strength by providing a double vessel wherein the cold inner portion consists of the internal shell of thin, flexible sheet of noble metal ensuring the necessary fluidtightness but having practically no inherent mechanical strength, whereas the warm outer portion consists of a mechanically rigid and strong external vessel surrounding said inner shell and made of conventional material such as ordinary steel or concrete, and of which the fluid-tightness is not necessarily perfect. Between these two tank shells a filling of rigid heat-insulating or like material is disposed for the multiple purposes of reducing the heat brought from the outside medium to a value corresponding to the desired evaporation rate, creating a temperature gradient suificient to make the temperature within the tank consistent with the specific conditions of use of the material stored therein, and retransmitting to said external tank or shell the hydrostatic pressure stresses exerted on the internal tank or shell.

It is the essential object of the present invention to improve the method of constructing the tank or vessel of the type set forth hereinabove and the device according to this invention is characterized in that the aforesaid internal shell is connected to the aforesaid external shell at spaced discrete points through fastening elements or brackets secured to said external shell and extending through the aforesaid intermediate insulating layer which is secured preferably to the aforesaid external shell.

According to another feature of this invention, in the vertical lateral wall constituting the cylindrical portion of the aforesaid internal shell the parallel corrugations of one of the aforesaid groups of corrugations are substantially rectilinear and preferably uniformly distributed along the generatrices of said wall, and the parallel corrugations of the other group are uniformly distributed along substantially horizontal parallel circumferences of said wall and at least one of the two respectively upper and lower aforesaid end walls of said internal shell comprises uniformly distributed radial corrugations each merging into a corresponding vertical corrugation of said lateral wall and defining therebetween respectively circular sectors each containing two substantially orthogonally intersecting groups of corrugations, the corrugations of one of said groups being substantially parallel to each other and those of the other group being either substantially radial or divided into series of parallel corrugations having a substantially radial direction.

According to another feature characterizing this invention, the corrugations of one of the aforesaid two groups of corrugations, in two adjacent ones of said sectors, are substantially parallel to the radial corrugation common to both sectors and merge into the corresponding vertical corrugations of the lateral wall, the corrugations of the other group extending substantially at right angles to said common radial corrugation.

The present invention is also concerned with a method of constructing the device set forth hereinabove, which method is of the type consisting in erecting firstly the aforesaid external shell constituting a self-supporting envelope on said base or basement prepared beforehand, and is characterized in that it consists in successively fastening the aforesaid prefabricated brackets on the internal face of said external shell; applying and securing the aforesaid intermediate insulation to said internal face by moulding same on site by injection moulding or by applying same by means of a spray-gun, or by assembling same in the form of prefabricated panels or blocks; prefabricating corrugated sheet metal elements having a substantially rectangular contour to constitute the aforesaid internal shell, and securing these elements to said brackets in mutually overlapping relationship by simultaneously joining and tacking said sheets and then welding same along their overlapping joints.

Finally, the invention is also concerned with the various applications resulting from the use of the aforesaid device and/ or method, notably for storing liquefied fluids at very low or very high temperature, as well as with the plants equipped with devices of this character.

Other features and advantages of the present invention will appear more clearly as the following description proceeds with reference to the attached diagrammatic drawings given by way of example only and illustrating a typical form of embodiment of the invention. In the drawings:

FIG. 1 illustrates in perspective view with parts broken away a specific form of embodiment of a tank constructed according to the teachings of this invention and built on a basement supported directly by the soil;

FIG. 2 illustrates on a smaller scale an external, sideelevational view of the same tank which, according to a modified form of embodiment of the invention, is carried by an elevated platform of slab structure supported by a piling or by a set of posts or piles driven in the soil;

FIG. 3 is a perspective view showing the geometric solid body corresponding to the tank shape and illustrating two mutually corresponding sectors in the respective top and bottom of the internal shell;

FIG. 4 illustrates the plane development diagram of a circular sector of one end Wall, for example the top or roof of the internal shell;

FIG. 5 illustrates the plane development diagram of a cylindrical sector of the lateral wall of the internal shell, which corresponds to a circular sector of the tank bottom and top;

FIG. 6 illustrates the plane development diagram of a modified form of circular sector of, say, the bottom of the internal shell, in which bottom all the corrugations of one group extend radially;

FIG. 7 is a fragmentary perspective view with parts broken away of one portion of the tank wall, showing the arrangement of the insulation means and a bracket for securing the internal shell;

FIG. 8 illustrates in fragmentary half-sectional view the central plug in the top of the tank;

FIG. 9 is a fragmentary sectional view of a pipe outlet provided in the tank wall;

FIG. 10 is a section showing on a smaller scale the tank and more particularly a scaffolding suspended from the top;

FIG. 11 is an enlarged elevational view, in longitudinal section, of a modification of the bracket shown in FIG. 7;

FIG. 12 is a plan view thereof;

FIG. 13 is a sectional elevational view of an auxiliary bracket; and

FIG..14 is a plan view thereof.

In the specific form of embodiment illustrated in FIG. 1, the tank according to this invention which is designated as a whole by the reference numeral 1 comprises an external shell or envelope 2 consisting either of ordinary steel or of reinforced concrete, or prestressed concrete, in order to constitute a strong or self-supporting structure. In FIG. 1, this extenal vessel or shell consists for example of prestressed concrete. The choice of the material for constructing this external vessel is dictated by economical factors. In fact, beyond a certain storage volume or capacity, the cost of a concrete structure becomes inferior to that of the ordinary steel structure. The storage tank illustrated in FIG. 1, intended for example for storing liquefied methane, may have for example a useful capacity of 20,000 cubic meters, corresponding approximately to an outer diameter of 37 meters and a height of about 24 meters for the external vessel.

This external self-supporting shell or vessel comprises a preferably flat bottom 3 laid on a base 4, a prestressed cylindrical lateral skirt or wall 5 having its lower portion embedded in the fiat bottom 3, and a roof or top 6 carried by the upper portion of the cylindrical Wall 5 which is built-in in said top which is preferably domed and convex upwards. This roof 6 is advantageously of cupola or spherical cap like configuration and designed to withstand the internal pressure corresponding to the vapour pressure considered as permissible for each specific application. As a rule and for an equivalent flexibility of use of the storage tank, the greater the storage capacity, the lower this maximal vapour pressure.

The nature of the base 4 depends on the characteristics or mechanical strength properties of the soil 7. Thus, in the case of a sufliciently strong or firm soil 7, it will be advantageous to use a base of the type illustrated in FIG. 1, which comprises from bottom to top a foundation layer consisting of a bed or raft of crushed pebbles 8 covered by a sand bed or layer 9 supporting directly the fiat bottom 3 of the tank. To avoid a gradual freezing of the soil under the tank, heating lines 10 are embedded, incorporated or integrated in the sand layer 9. These heating lines may consist of eelctrical heating resistances or of ducts permitting the circulation of a fluid heated or not beforehand.

FIG. 2 illustrates a modified form of embodiment of i the basement in the case of a rather loose soil. In this case, the tank 1 is supported by a platform or slab 11 for example of reinforced concrete extending up to a certain level above the ground surface and supported by a piling or the like 12 for example in the form of piles driven into the soil. Thus, an intermediate air gap is left between the tank bottom and the soil proper.

In this self-supporting external envelope or shell 2 an internal shell or envelope 13 completely enclosed and surrounded by said external shell 2 is mounted and spaced from said external shell to provide an intermediate gap or interval filled with a heat-insulating material 14 preferably secured to the inner face of the external shell 2 and supported thereby. The internal shell '13 consists of an envelope having a relatively thin wall constituting a kind of elastic, flexible or yielding membrane consisting for example of l-millimeter thick stainless steel sheet and having formed therein a network or pattern of mutually orthogonally intersecting corrugations, ribs or pleats divided into at least two groups of respectively parallel corrugations. These corrugations may be for example of the type described in the US. Patent application Ser. No. 374,042, now Pat. No. 3,299,398, filed on June 10, 1964, in the name of the applicant, for: Corrugated Sheet- Like Yieldable Wall Element and Vessels or Tanks Made Thereof.

The substantially parallel corrugations of each group are mutually spaced by a distance greater than the width of the waves constituting the other group of corrugations, whereby the orthogonally intersecting corrugations of the aforesaid pattern in the lateral wall form therebetween in the lateral wall plain or smooth areas 15 having a substantially rectangular or square contour, and all these corrugations have their convex side projecting preferably inwardly from the inner side of shell 13, without any outward projection of material from the opposite or outer side of said shell.

The substantially parallel corrugations 16 of one of the aforesaid groups or series of corrugations are advantageously continuous and constitute preferably the vertical corrugations of the cylindrical vertical wall 17 of the internal shell or envelope 13, whereas the substantially parallel corrugations 18 of the other group or series of corrugations are divided into wave sections by said continuous corrugations 16 which comprise respectively, in a manner known per se, at each intersection 19 with a corrugation 18, a pair of hollow impressions 20 at least in the crest portion of the continuous corrugations, said impressions being located in the vicinity and on either side of an intersection node 19. These impressions 20 are advantageously substantially in the form of a concave or re-entrant dihedron with the edge thereof directed substantially across the longitudinal direction of the continuous corrugation 16 concerned. The corrugations of both groups are visible in a detailed manner and on a larger scale in FIG. 7.

In the lateral cylindrical wall 17 of the internal shell, the vertical parallel corrugations 16 which extend substantially in the direction of the generatrices of said wall as well as the horizontal parallel corrugations 18 distributed along spaced parallel circumferences on said lateral wall, are for example equally space-d from each other in each group of corrugations.

At least the bottom 21 of the internal shell 13 and preferably also the roof 22 of said internal shell are corrugated according to a specific pattern. Each one of the bottom and top will thus comprise radial corrugations 23 extending from the center of the circular bottom and top to the outer periphery thereof. These radial, substantially rectilinear corrugations, advantageously of the type corresponding to the aforesaid continuous corrugation 16, are disposed for example at equally spaced angular intervals about the center of said bottom and top so as to divide it into substantially identical circular sectors 24. FIG. 1 illustrates in details a typical form of embodiment of this specific configuration of the bottom 21 of the internal shell of the tank. Each radial, substantially horizontal corrugation 23 merges into a corresponding vertical corrugation 16 of the cylindrical lateral wall 17. In each separate pair of adjacent sectors 24 having in common a radial corrugation such as 23', there is on the one hand a group of substantially parallel longitudinal corrugations 25 of the continuous type, which are preferably equally spaced from each other and substantially parallel to said common radial corrugation 23', and on the other hand a group of substantially rectilinear transverse corrugations 26, preferably equally spaced from one another, intersecting substantially orthogonally said continuous longitudinal corrugations 25. In each separate pair of adjacent sectors 24 which are contiguous along a common radial corrugation 23, the two groups of orthogonally intersecting corrugations 25 and 26 are substantially symmetrical in relation to said common radial corrugation 23', and the transverse corrugations 26, which are respectively perpendicular to the longitudinal corrugations 25, merge into the transverse corrugations of each adjacent pair of adjacent sectors 24, so as to form on said bottom and top substantially similar, or homothetic and concentric convex regular polygons. The transverse corrugations 26 will thus intersect obliquely, that is, not perpendicularly, the two endmost radial corrugations 23 limiting each pair of adjacent sectors 24, which endmost radial corrugations 23 will thus admit as the bisectrix of their angle the radial corrugation 23 common to the two adjacent sectors of the pair of adjacent sectors concerned. These transverse corrugations 26 are similar to the aforesaid corrugations 18.

The longitudinal corrugations 25, which are parallel respectively to the radial corrugations 23 common to each separate pair of adjacent sectors 24, extend from the outer periphery of the bottom or top towards the interior or center, and are respectively and successively of a length decreasing inwardly with their increasing distance from the common radial corrugation 23 to which they are parallel, and they terminate preferably in a plain area 15 between tWo successive corrugations, whereby they extend short of the center of the bottom or top. The radial corrugations 23 and 23' are also limited inwardly either by a stop plate 27 or the like, or by the edge of a central orifice formed through the bottom or top of the internal shell 13, so that they cannot converge right up to the center. Advantageously, the circular sectors of the bottom and roof portions of the internal shell 13 correspond to each other as shown in FIG. 3. Thus, the bottom and top are divided for example into twenty identical circular sectors having a central angle of 18 degrees, constituting for example ten separate pairs of adjacent sectors disposed symmetrically in relation to the common radial corrugation 23 of each pair of adjacent sectors. The internal shell 13 constituting a flexible or yielding or deformable membrane is completely supported by the intermediate insulating layer 14 against which it bears with its entire outer surface and which transmits practically all the stresses exerted by the contents of the tank upon said shell 13. This shell or envelope 13- advantageously consists of an assembly of prefabricated corrugated sheet metal elements juxtaposed and welded to each other. The orthogonally intersecting corrugations are formed in each prefabricated sheet element by using special tools for example of the type described in the US. patent application Ser. No. 379,450, now Pat. No. 3,343,397, filed on July 1, 1964, in the names of Gilbert Fournier and the applicant, for: Automatic Corrugating Machine for Impressing Two Secant Sets of Parallel Corrugations in Sheet-Metal Stock, which permits of manufacturing these elements at a high rate in two successive steps. Each one of the aforesaid rectangular corrugated sheet metal elements is advantageously so orient d that its edges or sides are substantially parallel to the two perpendicular directions of the aforesaid two groups of orthogonally intersecting corrugations, with its longer sides preferably parallel to said continuous or longitudinal corrugations and its edges disposed between two successive parallel corrugations. The same tools aforesaid may be used for manufacturing the bottom and top sheet metal elements corrugated respectively according to two groups of orthogonally intersecting corrugations and wherein the substantially radial arrangement of the longitudinal corrugations 25 is obtained by the successive loss or omission of the marginal waves in the vicinity of the radial waves 23. Thus, in each bottom or roof, the longitudinal waves 25 of decreasing length terminate each one towards the bottom or roof center on a short transverse edge limiting the transverse joint between two radially successive sheet-metal elements. FIG. 4 illustrates a circular sector 24 developed in a plane and taken for example from th roof 22, wherein the crest lines of the radial corrugations 23 and longitudinal corrugations 25 are shown in solid lines, the crest lines of the transverse corrugations 26 being shown in broken lines. The junctions between adjacent sheet-metal elements are shown in chain-dotted lines. FIG. 5 shows the development in a plane of the segment or portion of the cylindrical lateral wall corresponding to this circular sector 24 shown in FIG. 4, the crest lines of the continuous vertical corrugations 16 being shown in solid lines while the chain-dotted lines designate the junctions between adjacent sheet-metal elements.

According to another form of embodiment two groups of intersecting corrugations formed in the bottom or roof comprise the above-dcfined group of corrugations 26 constituting concentric regular polygons and another group of corrugations all of which are exclusively radial.

FIG. 6 illustrates a typical form of embodiment of this structure in the form of a bottom or top circular sector 24 developed in a plane, wherein the crest and base lines of the corrugations constituting the two groups of corrugations are shown diagrammatically in solid line. The chain-dotted lines designate the junctions or cut edges of the adjacent sheet-metal elements or panels constituting the bottom or top. In this example, each transverse corrugation 26', instead of constituting a single side of the poygon in each sector (as shown for example in FIGS. 1 and 4) constitutes several successive adjacent sides of said polygon, and each radial corrugation 23 extends substantially at right angles to all the parallel sides (constituted by corrugations 26) of the polygon intersected thereby. In this case, each polygon side is intersected by only one radial corrugation constituting in a way its mediatrix. These radial corrugations 23" consist for example of alternately long corrugations 23"a and'short corrugations 23"b, 23"c directed towards the bottom or top center. Each sector such as 24 may thus comprise two endmost long radial corrugations 23"a, a mean central radial corrugation 23"b and two intermediate short radial corrugations 23"c interposed respectively between the central corrugation 23"b and each endmost corrugation 23"a, the configuration of the sector being substantially symmetrical with resp ct to said central corrugation.

The wall of the roof or top 6, 22 of the tank has a central orifice 28 formed therethrough to permit the passage of the various necessary piping, conduits and equipments. To this end, the central orifice 28 of the roof is closed or sealed by a plug or like stopper 29 bolted to a flange 30 rigid with the tank and comprising a manhol or inspection hole 31 giving access to the interior of the tank and providing the passages for the necessary piping 32, ducts, gauges, measuring instruments and control apparatus. The plug 29 may consist if desired wholly of stainless steel and since it is detachable it affords an easy access to the interior of the tank during the entire period required for mounting the insulation and the internal shell, the manhole provided centrally thereof being adapted to be closed but easily opened for inspection of the tank inner space. The piping inl ts and outlets are formed directly through the plug 29. FIG. 8 illustrates a detail of the upper plug 29 which may be for example of the type disclosed in the US patent application Ser. No. 447,667, now Pat. No. 3,361,286, filed on Apr. 13, 1965, in the name of the applicant, for: Access Hole Construction Notably for Tanks Containing Liquefied Gas and comprising an external structure 33 bolted along its outer periphery 34 to the fixed flange 30 of the tank with the interposition of a sealing gasket 35. This metal structure 33 carries on its inner face a block of heat-insulating or like material 36 fitting into the hole 28 formed through the wall of the roof or top of the tank.

Piping outlets 37 are provided at the bottom of the tank and one of them is visible in FIG. 1. Each piping outlet extends substantially horizontally through the cylindrical lateral wall of the tank and FIG. 9 illustrates on a larger scale a detail of such a piping outlet. A through hole is formed in the tank wall and has fitted therein a duct 38 for example of stainless steel having its inner end welded as at 39 to the sheet metal of the internal envelope 13, its outer end projecting outwardly from the tank and comprising an end flange 39. A flanged tubular socket 40 is secured to the outer wall of the tank 2 and surrounds substantially coaxially the aforesaid duct 38 to define therewith an annular space filled with heat insulating or like material 41; The flange 39 is assembled by means of bolts, screws, studs or the like 42 with the flange of the tubular socket 40, a relatively thick insulating gasket 43 being interposed to constitute a kind of washer or the like.

As a rule, all the tank portions exposed to the very low temperatures of the fluids to be stored are made of a material having a satisfactory resistance to low temperature and a relatively low coefficient of heat conductibility, such as stainless steel.

The top or roof of the tank is advantageously formed with a series of scalable orifices 44 disposed substantially along a circumference preferably coaxial with the tank and respectively providing for the passage of suspension cables, ropes or chains 45 supporting at least one movable scaflolding platform or the like 46, disposed substantially horizontally inside the internal shell 13. This vertically movable platform is used for possible works to be performed on the inner Walls of the tank (see FIG. The through orifices 44 are heat insulated from the other portions of the roof or top.

The internal envelope or flexible membrane 13 is atattached to the self-supporting external shell or tank 2 by mean of brackets 47 distributed preferably uniformly with regular intervals and having for example the configuration illustrated in FIG. 7 showing the details of such a bracket 47. Each bracket 47 may be metallic, for example of stainless steel having a relatively low coefficient of heat conductibility to permit a substantial reduction in the heat transfer bridges. Each bracket comprises a structure 48 having at least four longitudinal radial fins of relatively thin sheet metal, these ribs having substantially the shape of a triangle or rectangular trapezium and being disposed crosswise or radially, with their common axis substantially perpendicular to the wall of the aforesaid external shell 2 to which they are attached by their large base. This structure 48 comprises at its reduced inner end a member 49 for fastening the aforesaid internal shell 13. Each bracket 47 is welded either directly to the inner wall of the external shell 2 if the latter is a metal shell, or alternatively, if this external shell is a concrete structure (as shown in FIG. 7) to a base plate 50 embedded, sealed or fitted in the concrete wall. These base plates 50 may consist of ordinary steel.

The function of these brackets is to receive and transmit the tensile stresses exerted on the flexible membrane 13 of the internal shell during the contraction resulting from the presence of the cold product in the storage tank. Each bracket must therefore have a minimum cross-sectional passage area for the heat or thermal flux coming from the outside, which accounts for the particular shape illustrated in FIG. 7. The buckling of the edges of fins 48 as a consequence of the possible bending of the bracket is advantageously avoided by the provision of at least one transverse stiffening gusset 51 interconnecting or bracing a pair of adjacent fins so as to reinforce the dihedral angle formed thereby.

The aforesaid fastening member 49 advantageously consists of a block in the form of an internally screwthreaded socket coaxially solid with the bracket structure 48 and adapted to be engaged by a fastening screw 52 passing through the wall of the internal shell 13 to clamp the latter against the bracket, a rigid insulating washer 53 for example of asbestos being preferably interposed therebetween. Each screw 52 is used for anchoring the membrance 13 and the heads of all the screws 52 are advantageously welded continuously around their periphery to the underlying sheet-metal panel of said internal shell 13.

As a rule, the sheet-metal elements constituting the internal shell or membrane 13 are assembled with one another along their edges forming overlapping joints welded along a continuous seam. Such joined sheet-metal elements 54 and 55 are shown in FIG. 7 with their welded overlapping joints 56. In this case, the head of each screw 52 clamping a sheet metal element such as 54 is covered by the marginal portion of the adjacent sheet metal element 55. The brackets 47 are preferably so distributed as to lie on the rectangular areas bounded by the corugations of membrane 13. FIG. 4 shows orifices 57 formed through the sheet elements to permit the passage of said fastening screws 52.

The intermediate insulation or lagging 14 of the tank advantageously consists of a rigid material known per se, such as expanded synthetic or plastic material, for example rigid expanded polyurethane, rigid expanded polyvinyl chloride or the like. The insulating material such as polyurethane is advantageously injection-moulded on the site by directly injecting the insulating material into a kind of shuttering or form divided into compartments, consisting of elements 58, 59 and subsequently left in the structure. FIG. 7 illustrates a compartment of this shuttering of which the outer wall consists of the inner face of the external shell 2 which may consist either of concrete as shown in FIG. 7, or of steel sheets, the lateral walls of the compartment consisting of prefabricated insulating plates or panels 58 glued directly at right angles or edgewise to said inner face of said external shell, and the inner wall of said compartment and therefore of the shuttering consists of compact or high-density prefabricated insulating plates 59 substantially parallel to the wall of the external shell and glued to the edge or end of the lateral partitions 58. Thus, each compartment of the shuttering is approximately of parallelepipedic configura tion with at least six sides or faces, two adjacent compartments being separated by and adjacent to a common partition 58. The sheet-metal elements of the internal shell 13 bear directly againstthe inner exposed face of the inner insulating plates 59. In the case of polyurethane, the insulating plates 58 forming the lateral partitions or walls of the compartments will have for example an average thickness of 50 to 60 millimeters and be substantially in the form of rectangular, for example 1,500-mm. long 170-mm. wide panels. This shuttering will remain of course as a permanent insert and will constitute an integral part of the aforesaid intermediate insulation or lagging. The exact value of the insulation thickness will be set by the specific service conditions contemplated and may lie for example in the range of from 200 to 300 mm. in the case of rigid expanded polyurethane to avoid on the one hand cold spots on the external shell at the location of the brackets 47 and on the other hand an excessive development or length of these brackets.

The lagging of the tank roof 6 will advantageously be applied by gun-spraying, and will be subsequently smoothened up for the other application methods are less convenient to use due to the double curvature of the wall.

After having secured the brackets and applied the intermediate lagging or insulation on the inner face of the external shell 2, the tank construction method comprises the fitting of the corrugated sheet-metal elements constituting the internal shell which are assembled with one another by clamping same by means of the fastening screws 52 and locked in position by means of a preliminary close tacking of the overlapping joints. The sheetmetal elements are subsequently welded to each other for example by carrying out the welding operation in an inert gas atmosphere such as argon, and without using filler metal, the heads of screws 52 being locked beforehand in position by means of a peripheral weld seam also acting as a sealing Weld.

According to an alternative form of embodiment of the brackets interconnecting the outer shell 2 and the inner shell 13, shown on FIGS. 11 and 12, each bracket, instead of consisting of a fin assembly as shown on FIG. 7, comprises a single tube member 60, secured at its outer end to the outer shell 2 and welded at its inner end to the inner shell 13. If the outer shell is for example made of concrete, the outer end of tube 60 is conveniently flanged as at 61 and welded therearound to the base or anchoring plate 50 which is provided preferably with at least one expansion bolt or the like 50 sealed into the concretewall of shell 2. At its inner end, the tube 60 is closed by an end plate 62 preferably welded inside the tube and provided with a stud pin or the like 63 welded to said end plate in substantially coaxial relation to the tube and projecting outwards therefrom. The free outside portion of said stud pin extends through a corresponding hole 64 provided in the wall of inner shell 13, which hole is substantially larger than the diameter of the stud pin. The free projecting end 65 of the stud pin is threaded to temporarily receive a removable tightening nut 66 for mounting purposes. A bearing plate or washer 67 is tightly welded to stud pin 63 extending therethrough, so as to be located between tube 60 and inner shell 13 which latter bears against said plate and is welded in sealing relationship thereto along the edge of hole 64. A chock or spacer element 68, made from asbestos for example is preferably interposed between plate 67 and tube 60 to take up the clearance due to the manufacturing tolerances of the intermediate insulating material 14. Each bracket 60 having been pre fabricated as an integral unit provided with its parts 62, 63 and 67 and secured to the outer shell 2, the method of connecting it to the inner shell wall 13 consists, before the welding step, in firmly applying said Wall against hearing plate 67 by means of a wheel-shaped washer with spokes 69 (see FIG. 12) mounted by its hub on stud pin 63 and adapted to be pressed against the inner face of wall 13 by the nut 66 screwed on the threaded end of the stud pin. The welding operation is then carried out by passing through the voids in washer 69. After the welded joint has been achieved along the edge of hole 64, the parts 66 and 69 are removed.

Between the brackets 47 of FIG. 7 or 60 of FIG. 11 (called main brackets) are advantageously provided auxiliary brackets, one of which is shown on FIGS. 13 and 14. Each auxiliary bracket is adapted to sustain tractive forces only so as to resist any overpressure occurring in the intermediate insulating space 14 between the outer and inner shells, or any depression or vacuum occurring inside the inner shell. To this end, each auxiliary bracket consists of a bracing or tie-rod 70 secured at its outer end to the outer shell 2, for example by means of an anchoring plate 71 similar to plate 50. The inner end 72 of rod 70 projects through a hole 73 in wall 13 and is threaded to temporarily receive a nut 74 for clamping a wheelshaped pressure Washer with spokes 75 adapted for the same mounting purposes as mentioned hereinabove with reference to FIGS. 11 and 12. A bearing plate 76 similar to plate 67 is carried by, for example tightly welded to, rod 70 for application of wall 13 thereagainst, which wall is tightly Welded to said plate along the edge of hole 73 which is larger than the diameter of rod 70.

Of course, the invention should not be construed as be ing limited by the specific form of embodiment described and illustrated herein which are given by way of example only.

What I claim is:

1. A land vessel construction for uses such as a nuclear reactor tank and as a stationary container for the storage of fluids, rising above ground level and consisting of a multiple-wall casing comprising: a substantially cylindrical, vertical, outer shell of self-supporting structure having a dome roof and a flat bottom resting on a basement; at least one inner fluid-tight shell spaced from said outer shell and made of relatively thin, flexible, corrugated sheetmetal stock formed with a pattern of corrugations, generally intersecting each other at right angles and arranged in at least two sets of substantially parallel corrugations; and at least one layer of relatively rigid heat-insulating material attached to said outer shell and filling the intermediate space left between said shells and supporting the pressure of said inner shell bearing thereagainst; said inner shell being connected to said outer shell at discrete points by means of fastening brackets secured to said outer shell in spaced relationship to each other and extending through said layer of insulating material; and wherein, in the lateral vertical wall of said inner shell, the parallel corrugations of one set are substantially straight and uniformly spaced from each other and extend along the generating lines of said wall, whereas the parallel corrugations of the other set extend in equally vertically spaced relationship along substantially horizontal circumferences of said wall, at least one of the two opposite end walls of said inner shell, which form the top and the bottom thereof, respectively, being formed with substantially uniformly distributed, radially extending corrugations joining each one a corresponding vertical corrugation of said lateral wall to define therebetween respective circular sectors containing each one two perpendicularly intersecting sets of corrugations, whereby the corrugations of one lastnamed set extend in substantially parallel relation to each other and the corrugations of the other set extend in an at least approximately radial direction.

2. A vessel according to claim 1, wherein said outer shell is metallic and each bracket is direct y welded thereto.

3. A vessel according to claim 1, wherein said outer shell is made of concrete and each bracket is welded to.

a base plate anchored in the concrete wall of said shell.

4. A vessel according to claim 1, wherein said intermediate layer of insulating material consists of rigid material selected from the group comprising expanded polyurethane and expanded polyvinyl chloride.

5. A vessel according to claim 1, wherein the parallel corrugations of each set are spaced from each other by a distance greater than the Width of the raised wave portions of the corrugations of the other set, so as to define therebetween, at least in the lateral Wall of said inner shell, smooth, non-corrugated quadrangular areas, and all the corrugations have their convex portions projecting inwards from the inner side of the sheet metal, without any material protruding outwards from the outer side of said sheet metal.

6. A vessel according to claim 5, wherein the parallel corrugations of one set, forming the vertical corrugations in said lateral wall and the radially directed corrugations in said end wall, are continuous, whereas the parallel corrugations of the other set are discontinuous and divided into aligned wave sections by said continuous corrugations, each continuous corrugation comprising, at each intersection with a discontinuous corrugation, a pair of transverse hollow impressions formed at least in the crest portion of said continuous corrugation and located in the vicinity and on either side, respectively, of said intersection.

'7. A vessel according to claim 1, wherein the corrugations of one of said sets in any two adjacent aforesaid sectors, are substantially parallel to that radial corrugation which is common to the two sectors and'merge into the corresponding vertical corrugations, respectively, of said lateral wall, whereas the corrugations of the other set are substantially perpendicular to said common radial corrugation.

8. A vessel according to claim 7, wherein, in each distinct pair of said adjacent sectors, those corrugations which are parallel to said radial corrugation that is common to both sectors, are substantially symmetrical with respect to said common radial corrugation whereas those corrugations, which are transverse and perpendicular to said first-named corrugations, meet the three successive radial corrugations defining said pair of adjacent sectors by merging into the transverse corrugations of each neighbouring pair of adjacent sectors, so as to form regular concentric and homothetic polygons.

9. A vessel according to claim 8 wherein, in each distinct pair of said adjacent sectors, those corrugations, which are parallel to that radial corrugation which is common to both sectors, are all the more shorter and endinwards all the more farther from the center respectively, as their distance from said common radial corrugation increases.

10. A vessel according to claim 9, wherein said radial corrugations of said end wall are limited inwards by a central stop plate integral with said end wall.

11. A vessel according to claim 10 having on the one hand main brackets each of which comprises a tubular member connected at its outer end with said outer shell and closed at its inner end by an end plate carrying a stud pin in substantially coaxial relation to said tubular member, said stud pin extending through and being connected in sealing relationship with a bearing plate for application of the inner shell wall thereagainst and having a threaded inner end projecting through a corresponding hole of substantially larger size formed in the inner shell wall which is welded in sealing relation to said underlying bearing plate along the edge of said hole; and on the other hand spaced auxiliary brackets between said main brackets for interconnecting said inner and outer shells, each auxiliary bracket consisting of a tie-rod connected at its outer end with said outer shell and having a threaded inner end projecting through a corresponding hole of substantially larger size, formed in the wall of said inner shell, said rod extending at its inner end through and being connected in sealing relationship with a bearing plate for application of said inner shell wall there- 12 against, which wall is tightly welded thereto along the edge of said hole, said inner shell consisting of juxtaposed sheet-metal elements welded to each other along lap oints.

12. A vessel according to claim 1, having its roof formed with at least one central orifice closed by a removable plug means bolted to a flange integral with said roof and formed with a manhole and passages for ducts, pipings, gauges, measuring instruments and control devices.

13. A vessel according to claim 12, fitted withpiping outlets each of which comprises: a passageway extending through the wall of said inner shell, said intermediate insulating material and said outer shell; a pipe built in said passageway and welded at its radially inner end to the wall of said inner shell, said pipe projecting outwardly beyond said outer shell with its outer end portion provided with an outwardly turned end flange; a tubular support with out-turned flanges at both ends, the inner flange of said support being secured to the outer face of the said outer shell and substantially coaxially surrounding said pipe to define an annular space between said pipe and said support and heat-insulating material filling said annular space, the end flange of said pipe and the outer flange of said tubular support being connected together by bolt means with a thick insulating gasket interposed between said connected flanges.

14. A vessel according to claim 12, wherein said roof is formed therethrough with a plurality of scalable holes arranged in spaced relationship along at least one circumference substantially coaxial with said outer shell and adapted for the passage of suspension cables and chains supporting at least one depending platform movable within said inner shell.

15. A land vessel construction for uses such as a nuclear reactor tank and as a stationary container for the storage of fluids, rising above ground level and consisting of a multiple-wall casing comprising: a substantially cylindrical, vertical, outer shell of self-supporting structure having a dome roof and a flat bottom resting on a basement; at least one inner fluid-tight shell spaced from said outer shell and made of relatively thin, flexible, corrugated sheet-metal stock formed with a pattern of corrugations, generally intersecting each other at right angles and arranged in at least two sets of substantially parallel corrugations; and at least one layer of relatively rigid heatinsulating material attached to said outer shell and filling the intermediate space left between said shells and supporting the pressure of said inner shell bearing thereagainst; said inner shell being connected to said outer shell at discrete points by means of fastening brackets secured to said outer shell in spaced relationship to each other and extending through said layer of insulating material; and wherein, in the lateral vertical wall of said inner shell, the parallel corrugations of one set are substantially straight and uniformly spaced from each other and extend along the generating lines of said wall, whereas the parallel corrugations of the other set extend in equally vertically spaced relationship along substantially horizontal circumferences of said wall, at least one of the two opposite end walls of said inner shell, which form the top and the bottom thereof, respectively, being formed with substantially uniformly distributed, radially extending corrugations joining each one a corresponding vertical corrugation of said lateral wall to define therebetween respective circular sectors containing each one two perpendicularly intersecting sets of corrugations, whereby the corrugations of one last-named set extend in substantially parallel relation to each other and the corrugations of the other set extend in an at least approximately radial direction; each bracket comprising at least four radial, longitudinally extending, relatively thin sheet-metal fins of substantially trapezoidal shape, arranged about the axis of the bracket with the bracket axis substantially normal to the wall of said outer shell to which said fins are secured by their large base; each bracket comprising, at its reduced inner end, a fastening member for said inner shell.

16. A vessel according to claim 15, wherein at least one transverse stiflfening gusset interconnects two adjacent fins of each bracket to reinforce the dihedral angle formed therebetween.

17. A vessel with main brackets according to claim 15, comprising spaced auxiliary brackets between said main brackets for interconnecting said inner and outer shells, each auxiliary bracket consisting of a tie-rod secured at its outer end with said outer shell and having a threaded inner end projecting through a corresponding hole of substantially larger size, formed in the wall of said inner shell, said rod extending at its inner end through and being secured in sealing relationship to a bearing plate for application of said inner shell wall thereagainst, which wall is tightly welded thereto along the edge of said hole.

18. A vessel according to claim 15, wherein the fastening member carried by each bracket consists of a tapped socket coaxially integral with said bracket and adapted to receive a fastening screw extending through the sheetmetal wall of said inner shell.

19. A vessel according to claim 18, wherein the head of each fastening screw is welded along its periphery to the underlying sheet-metal wall of said inner shell.

20. A vessel according to claim 18, wherein said inner shell consists of a plurality of juxtaposed sheet-metal elements welded to each other along lap joints, so that each fastening screw head is covered by the overlapping edge portion of a sheet element.

21. A land vessel construction for uses such as a nuclear reactor tank and as a stationary container for the storage of fluids, rising above ground level and consisting of a multiple-wall casing comprising: a substantially cylindrical, vertical, outer shell of self-supporting structure having a dome roof and a flat bottom resting on a basement; at least one inner fluid-tight shell spaced from said outer shell and made of relatively thin, flexible, corrugated sheet-metal stock formed with a pattern of corrugations, generally intersecting each other at right angles and arranged in at least two sets of substantially paralle corrugations; and at least one layer of relatively rigid heat-insulating material attached to said outer shell and filling the intermediate space left between said shells and supporting the pressure of said inner shell bearing thereagainst; said inner shell being connected to said outer shell at discrete points by means of fastening brackets secured to said outer shell in spaced relationship to each other and extending through said layer of insulating material; and wherein, in the lateral vertical wall of said inner shell, the parallel corrugations of one set are substantially straight and uniformly spaced from each other and extend along the generating lines of said wall, whereas the parallel corrugations of the other set extend in equally vertically spaced relationship along substantially horizontal circumferences of said wall, at least one of the two opposite end walls of said inner shell, which form the top and the bottom thereof, respectively, being formed with substantially uniformly distributed, radially extending corrugations joining each one a corresponding vertical corrugation of said lateral wall to define therebetween respective circular sectors containing each one two perpendicularly intersecting sets of corrugations, whereby the corrugations of one last-named set extend in substantially parallel relation to each other and the corrugations of the other set extend in an at least approximately radial direction; each bracket comprising a tubular member secured at its outer end to said outer shell and closed at its inner end by an end plate carrying a stud pin in substantially coaxial relation to said tubular member, said stud pin extending through and being secured in sealed relationship to a bearing plate for application of the inner shell wall thereagainst, and having a threaded inner end projecting through a corresponding hole of substantially larger size formed in the inner shell wall which is welded in sealing relation to said underlying bearing plate along the edge of said hole.

22. A vessel according to claim 21, wherein a heat insulating washer is interposed between said bearing plate and the inner end of said tubular member.

23. A vessel with main brackets according to claim 21, comprising spaced auxiliary brackets between said main brackets for interconnecting said inner and outer shells, each auxiliary bracket consisting of a tie-rod secured at its outer end to said outer shell and having a threaded inner end projecting through a corresponding hole of substantially larger size, formed in the wall of said inner shell, said rod extending at its inner end through and being secured in sealing relationship to a bearing plate for application of said inner shell wall thereagainst which wall is tightly welded thereto along the edge of said hole.

References Cited UNITED STATES PATENTS 1,799,234 4/1931 Huff.

1,993,500 3/1935 Benner 220-15 2,744,042 5/ 1956 Pace.

2,777,295 1/1957 Bliss et al 220 -14 X 2,952,987 9/1960 Clauson 22010 X 3,088,621 5/1963 Brown.

3,112,043 11/1963 Tucker 22015 X 3,151,416 10/1964 Eakin et al.

3,158,459 11/1964 Guilhem 22015 X 3,270,700 9/ 1966 Kohn et al.

3,332,386 7/1967 Massac 22015 X FOREIGN PATENTS 1,454,271 8/1966 France.

JOSEPH R. LECLAIR, Primary Examiner J. R. GARRETT, Assistant Examiner US. Cl. X.R. 

